Access door



sept- 1962 D. B. FlTZ PATRICK ACCESS DOOR Filed Nov. 24, 1958 2 Sheets-Sheet l m mm INVENTOR. Donald B. FH'zParrick 'AT TORNEY p 25, 1962 D. B. FlTZ PATRZCK 3,055,321

' ACCESS DOOR Filed Nov. 24, 1958 2 Sheets-Sheet 2 FIG.3

FIG.2

. INVENTOR.

-| BY Donald B. Firz Parrick ATTORNEY United States Patent 3,055,321 ACCESS DOOR Donald B. Fitz Patrick, Akron, Ohio, assignor to The Babcock & Wilcox Company, New York, N.Y., a corporation of New Jersey Filed Nov. 24, 1958, Ser. No. 775,833 6 Claims. (Cl. 110--173) The present invention relates in general to furnaces and more specifically to a closure assembly for sealing access openings in furnace walls, which define a combustion chamber for generating high temperature gases, boiler walls, associated ductwork and the like.

An object of this invention relates to the provision of means by which the door is automatically latched in a positive manner as the door is moved into its fully closed position, and which through suitable manual operation of the same means, may be readily unlatched for door movement to any desired opened position within its total available range of movement.

Another object is to provide a novel latching means for a closure which is rendered initially operative either by the centrifugal force created in swinging the closure to a closed position or by a positive camming action of the latch means with a co-operating catch in the event the closure is moved toward closed position with insuflicient force to render the latch centrifugally operative, and which in either event is finally automatically actuated to latching position on the follow through, by a positive camming action.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which a specific embodiment of the invention is illustrated and described.

Of the drawings:

FIG. 1 is a fragmentary horizontal section of a furnace wall embodiment of the invention; the access door being shown in its fully closed and latched position with respect to a furnace wall access opening as defined by a door frame surrounding the opening; and the door being illustrated in open position as shown in dot-dash lines.

FIG. 2 is a front elevational view of the door and door frame assembly, with the door in its closed position as represented by the solid lines in FIG. 1;

FIG. 3 is a vertical section along line 3-3 of FIG. 2.

FIG. 4 is a partial horizontal section of the furnace wall and door showing the manner in which the latching means is made to contact a door frame portion so as to assume its final fully latched position as represented in FIG. 1.

In more detail, and referring first to FIGS. 1, 2 and 3, a door frame 5 is provided in an upright wall 6 of a furnace combustion chamber 7 so as to define a wall opening 8 through which access may be had to the interior of the chamber. In the illustrated embodiment the wall opening 8 is of a generally elliptical form, elongated in a vertical direction. Fluid heating tubes 9 are disposed generally in a row along the inner face of wall 6, with portions of the tubes adjacent the opening 8 being bent and arranged so as to embrace opposite sides of the furnace Wall opening.

A closure or door means including a door 10, of generally elliptical form, is provided at the outer side of furnace wall opening 8 so as to overlap the entire periphery of frame 5; a gasket 11 being provided between overlapping peripheral portions of the door and frame 5. The door 10 has connected thereto on the furnace side thereof a readily removable heat resisting liner 10A. As shown, the liner 10A is defined by a collar 12 of generally 3,055,321 Patented Sept. 25, 1962 frusto-conical form which projects into the furnace wall opening 8. Contained within the collar 12 is a filler 13 of heat resisting refractory material by which the door 10 is protected from direct exposure to high furnace temperatures. The refractory material or filler 13 is itself protected from overheating by fluid conducting tube lengths 14 embedded therein for conducting a suitable cooling fluid therethrough. Fluid is admitted to such tube lengths 14 through a lower fluid inlet connection 15 and is discharged therefrom through an upper fluid outlet con nection 1-6.

The door 10 and a door yoke 17 connected thereto are hingedly secured about a common pivot pin 18 connected to the frame 5 at one side of the opening 8. The yoke 17 pivoted to pin 18, intermediate the ends thereof, extends horizontally across the central area of the door, in outwardly spaced relation thereto, as represented in FIGS. 1 and 2. The door 10 is formed with a centrally located boss 19 which extends axially from the inner side of the door. A circular recess or bore 20 is formed in the boss to form a socket Within which the inner end of the handwheel stem 21 is retained by means including an outwardly flanged bushing 22. Thus the opening and closing of door 10 is readily effected through movement of the yoke '17 about pivotal axis 18. As seen in FIG. 3, an intermediate portion 21A of stem 21 is in continuous threaded engagement with a central portion 17A of yoke 17 so as to enable the pressure of door 10 against gasket 11 to be adjusted, either after the door has been moved into its closed position, or before the door is moved to open position.

In accordance with this invention a feature relating to door operation is the provision of a latch or yoke hook 23 which is pivotally connected to yoke 17 about pivot 24; and provides the means by which the door is automatically and positively latched when swung to close position to seal the Wall opening. In order to utilize this novel form of yoke hook 23, the door frame 5 is provided with a cooperating stationary catch 25 located at the side of the furnace wall opening 8, opposite to the side at which the pivot 18 of the yoke 17 is positioned. As seen in FIGS. 1 and 2 the catch has a portion 25A extending normal to the frame and a hook portion 25B extending laterally therefrom in a direction away from the furnace opening and spaced from the frame. The outer edge 26 of the laterally extending portion 25B is beveled or inclined toward the frame 5.

The latch or yoke hook 23 in accordance with this invention, pivoted at 24 to the yoke and forming an extension thereof, has a laterally extending portion 23A extending in the direction of the furnace opening 8 parallel to the frame. The inner edge is beveled outwardly to form a leading cam surface or edge 23B. At the base portion 23C of latch 23, adjacent the pivot 24, there is provided an inwardly extending striker portion 23D positioned so that it makes contact with the head of catch 25 on the follow through of the latch 23 as will be hereinafter explained.

Connected to the latch 23 and extending outwardly therefrom in a direction away from the opening is a weighted means in the form of a T-shaped manual handle 27. As will be hereinafter described the outwardly extended handle means 27 imparts additional momentum to the latch as it is rotated into latching position, as shown in FIG. 1.

The operation of the door assembly is as follows:

In swinging the door from open position as indicated in the dot-dash lines of FIG. 1 to closed position as shown by solid lines therein, the centrifugal force acting on latch 23 will cause the latch to pivot relative to the yoke 17 and about its axis or pivot 24 in outwardly or counter-clockwise direction as viewed in FIGS. 1 and 4.

The base end 28 of latch 23 engaging the shoulder of the bifurcated end portion or limiting means 173 of the yoke limits the rotation of the latch 23 relative thereto. Thus as the door approaches the closed position the leading edge 23B of the latch 23 clears catch 25, permitting the inwardly extending latch portion 23A to be positioned between the frame and lateral extending hook portion 258 of the catch, as viewed in FIG. 4. As the latch FIG. 1, the outboard position of the handle 27, due to its extended moment arm, imparts additional momentum to the latch as it is kicked into latching position to insure automatic latching. With the door thus latched the hand wheel 29 is rotated to apply final sealing pressure on the door. With the latch hook 23 disposed in horizontal alignment with the yoke pivot there is no tendency on the part of the yoke 17 to twist when pressure is applied to .the door.

To release the latch, the hand wheel 29 is turned to back off the stem 21 to relieve the pressure on the door. With the pressure relieved the handle 27 is manually pulled in a manner releasing the latch 23 and the door pivoted to open position.

In the event that the latch 23 is not rotated in a counter-clockwise direction about its pivot 24 when the door and yoke carried thereby is swung from open to closed position because of insufficient momentum, automatic and positive latching is still rendered possible by the structure described. If the centrifugal force is insufficient to rotate the latch outwardly, as hereinbefore described, the leading cam edge 23B of the latch 23 will strike the beveled edge 26 of the catch as the door approaches the closed position. The striking of the latch 23 on the .catch 25 results in a carnming of the latch outwardly or in a counter clockwise direction so that the inwardly turned hook portion 23A of the latch is positioned beyond the hook 25B of the catch as viewed in FIG. 4. On the follow through, as the door moves into final closing position, the striker 23D is brought into engagement with the head of the catch 25 causing the latch to be positively rotated in a clockwise direction and automatically kicked or cammed into closed engagement with the catch, as

hereinbefore described. Thus it is to be noted that with the improved latch 23 of this invention, the door in moving from open to closed position is automatically and positively latched whether the door is swung in a manner so 'as to create a sufficient centrifugal force to initiate the latching operation or whether the door is swung in a manner in which the centrifugal force is insufficient to initiate the latching operation. In either event the door is automatically and positively latched.

While the door is herein illustrated and described as having a particular design to heat resistant liner 16A, it is to be understood that as the liner A is rendered readily removable, other liners designed for other temperature conditions may be readily substituted for that herein shown and described. In this manner it will be apparent that the basic frame 5, door 10, yoke 17, and latch operating mechanisms 23, 25 may be used to seal access openings which open to various temperature zones of a furnace or other heated enclosure simply by attaching thereto, the properly designed liner as determined by the particular temperature to which the inner surface of the door is to be exposed.

While the instant invention has been disclosed with reference to a particular embodiment thereof, it is to be appreciated that the invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the .spirit or scope of the invention.

What is claimed is:

1. A closure assembly comprising a frame defining an access opening, a door means for sealing said opening, hinge means for hingedly connecting said door means to said frame for swinging between open and closed positions, a catch connected to said frame, and a latch having a leading cam edge, a following striker portion, and a base end portion, means for loosely pivoting said latch to said door means opposite the hinge means thereof, means on said door means adjacent said latch for limiting rotation of said latch as said latch is automatically freely rotated outwardly about its pivot means upon the application of a predetermined amount of centrifugal force created by the door swinging to closed position thereby enabling said leading cam edge of said latch to clear said catch, and said leading cam edge being adapted to engage said catch to earn said latch outwardly an amount sufficient for the latch to clear the catch in the event said door means is swung in a manner producing a centrifugal force insufficient to rotate said latch outwardly, and said following striker portion being adapted to engage said catch in either event as the door closes for automatically kicking said outwardly displaced latch into positive locking engagement with said catch.

2. A closure assembly comprising a frame adapted to circumscribe opening in a furnace wall, a door adapted to seal said opening, a readily removable heat resistant liner connected to said door on the furnace side thereof, a yoke carried by said door on the outer side thereof, hinge means connecting said door and yoke to said frame for swinging between open and close positions, said yoke having a bifurcated end portion opposite said hinge means, a catch fixedly connected to said frame opposite said door hinging means, said catch having an outwardly turned hook portion, and latch having a hook shaped portion and a following connected striker portion, said latch hook portion having a leading cam edge, means for pivoting the latch to said yoke opposite the hingedly connected end portions thereof so that in the event a determinate amount of centrifugal force is produced in swinging the door to closed position, the latch is automatically rotated outwardly about said pivoting means in the same plane in which the door and connected yoke is swung to clear the catch hook, said latch having a base end portion adapted to engage the -end of said bifurcated end portion to limit outward rotation of said latch about said pivot means and said leading cam edge being adapted to engage said catch hook to positively cam said latch outwardly in the event said door and yoke carried thereby is swung in a manner producing insuflicient centrifugal force to rotate said latch hook clear of said catch, said following striker portion being adapted to engage said catch in either event as the door closes for automatically kicking said outwardly rotated latch into positive locking engagement with said catch, and an outboard weighted means connected to said latch for imparting thereto added momentum to insure positive operation thereof.

3. A closure assembly comprising a frame adapted to circumscribe an opening in a furnace wall, a door adapted to seal said opening, a fluid cooled, readily removable, heat resistant liner connected to said door on the furnace side thereof, a yoke carried by said door on the outer side thereof, hinge means connecting said door and yoke to said frame for swinging between open and close positions, said yoke having a bifurcated end portion opposite said hinge means, a catch fixedly connected to said frame opposite said door hinging means, said catch having an outwardly turned hook portion, a latch having a hook shaped portion and a following striker portion connected thereto, said latch hook portion having a leading cam edge, means loosely pivoting the latch being pivotally between the bifurcated end portions of said yoke opposite the hinge means thereof so that in the event a determinate amount of centrifugal force is produced in swinging the door to closed position, the latch is automatically rotated outward- 1y about its pivot means in the same plane in which the door and connected yoke is swung to clear the catch hook, said leading cam edge being adapted to engage said catch hook to positively cam said latch outwardly to clear the catch hook in the event said latch is not rotated outwardly upon the closing movement of said door and yoke, said latch having a base end portion adapted to engage the end of said bifurcated portion to limit outward rotation of said latch about said pivot means and said striker portion being adapted to engage said catch in either event as the door closes for automatically kicking said outwardly rotated latch in positive locking engagement with said catch, an outboard weighted means connected to said latch for imparting thereto added momentum for insuring positive operation thereof and to serve as a handle for releasing said latch, and a screw threaded to said yoke and engaging said door for applying pressure thereto for positively sealing said door against the frame to seal said opening.

4. A closure assembly comprising a frame defining an access opening, a door means including a door yoke for sealing said opening, said yoke having opposed ends, hinge means connecting one end of said yoke to said frame for swinging between open and closed positions, a catch connected to said frame, a latch adapted to engage with said catch, means loosely pivoting said latch to the ot er end of said yoke so that said latch may be automatically and freely rotated outwardly about its pivoting means by a centrifugal force created in swinging said door means from open to closed positions, limiting means located on said yoke adjacent said latch, said latch having a base end portion adapted to engage said limiting means for limiting the rotation of the latch outwardly of the door means an amount suflicient for the latch to clear the catch as the door is swung to a closed position, and said latch having a striker means for engaging said catch in the outwardly rotated position of said latch as the door swings to closed position for automatically kicking the latch inwardly about its pivoting means into positive locking engagement with said catch.

5. A closure assembly comprising a frame adapted to define an access opening in a furnace wall, a door for sealing said opening, a yoke carried by said door, said yoke having opposed end portions, hinge means for connecting one end portion of said yoke to said frame for swinging between open and closed positions, and the other end of said yoke being bifurcated, a hook shaped catch connected to said frame, a hook shaped latch, means loosely pivoting said latch to bifurcated end portions of said yoke opposite the hinge connection, said latch having a base end adapted to engage the end of said bifurcated end portion of said yoke to limit outward rotation of said latch an amount sufficient for said latch to clear said catch upon the creation of a predetermined amount of centrifugal force in swinging the door and yoke carried thereby to closed position, said latch having a striker means engaging said catch as the door closes for automatically kicking said latch inwardly into positive locking engagement with said catch, and means carried by said yoke and engaging said door for applying pressure thereto for positive sealing of the door against the frame.

6. The invention as defined in claim 4 wherein said door means and latch connected thereto rotate about their respective pivoted connections in a horizontal plane.

References Cited in the file of this patent UNITED STATES PATENTS 1,432,591 Carll Oct. 17, 1922 1,769,979 Whittarn July 8, 1930 1,935,492 Warg Nov. 14, 1933 2,054,907 Mollet Sept. 22, 1936 2,129,926 Geske et al Sept. 13, 1938 2,800,519 Garrny July 23, 1957 2,820,002 Wolif Jan. 14, 1958 FOREIGN PATENTS 16,566 Great Britain 1891 89,952 Germany Dec. 21, 1896 

